<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        #grid {
            display: grid;
            grid-template-columns: 1fr 1fr 1fr;
            grid-gap: 10px;
        }
        #grid > div {
            background-color:aqua;
            padding: 30px;
            height: 100px;
        }
        #grid > div:nth-child(odd) {
            background: #ccc
        }
    </style>
</head>
<body>
    <div id="grid">
        <div>1</div>
        <div>2</div>
        <div>3</div>
        <div>4</div>
        <div>5</div>
        <div>6</div>
        <div>7</div>
        <div>8</div>
        <div>6</div>
        <div>7</div>
        <div>8</div>
    </div>
</body>
</html>